The present invention relates to an ink-jet recording apparatus which comprises an ink-jet type recording head mounted on a carriage, which travels in a widthwise direction of recording paper, and ejects ink droplets toward the recording paper so as to correspond to print data. More particularly, the present invention relates to a flushing controller suitable for use with a recording apparatus which records an image on paper having a large width.
Ink-jet recording apparatus can print small dots with a comparatively low noise level at high density, and hence they have recently been used in many printing applications, including color printing. Such an ink-jet recording apparatus comprises an ink-jet recording head which receives ink supplied from an ink cartridge, and paper feeder for feeding a recording sheet relative to the recording head. Text or an image is recorded on the recording sheet by causing the recording head to eject ink droplets to the recording paper while the recording head travels together with a carriage in a widthwise direction of the recording sheet. For example, a black recording head for ejecting black ink and a color recording head capable of ejecting various colors of ink, such as yellow, cyan, and magenta, are mounted on a single recording head. The ink-jet recording apparatus enables full-color printing through use of black ink, as well as printing of text, by changing the proportions of color inks to be ejected.
Such an ink-jet recording head performs a printing operation by ejecting ink, which is pressurized in a pressure generating chamber, as ink droplets by way of a nozzle. The ink-jet recording head suffers problems such as printing failures, which are caused by an increase in the viscosity of ink due to evaporation of a solvent by way of nozzle orifices, solidification of ink, adhesion of dirt or dust on the nozzle, or mixing of air bubbles into ink. In order to prevent the printing failures, the ink-jet recording apparatus is equipped with a capping unit for sealing the nozzle orifices of the recording head while the recording apparatus is in a non-printing mode
In the event that the nozzle orifices are clogged, the capping unit eliminates clogging in the nozzle orifices caused by solidification of ink or an ink ejecting failure due to mixing of air bubbles into the ink flow channel, by means of sealing the nozzle plate through use of a cap unit and suctioning ink by means of negative pressure imparted by a suction pump by way of the nozzle orifices. Further, the capping unit also has the function of preventing drying of the ink remaining in the nozzle orifices while the recording apparatus is in a non-printing mode.
Forced discharging operation, which is performed in order to eliminate clogging in the recording head or air bubbles mixed into the ink flow channel, is called cleaning operation. The cleaning operation is performed when a printing operation is resumed after the recording apparatus has remained in an idle mode for a long period of time or when the user actuates a cleaning switch after observing degradation in the quality of a recorded image. The cleaning operation involves removal of ink droplets from the recording head by means of negative pressure applied through suction.
The capping unit also has a capability of ejecting ink droplets by application to the recording head of a drive signal that is irrelevant to printing. This function is called flushing operation. The flushing operation is performed at predetermined cycles for the purposes of: recovering meniscuses, which are irregularly formed in the vicinity of nozzle orifices of the recording head as a result of wiping action of a wiping blade during the cleaning operation; and preventing clogging in the nozzle orifices from which a small amount of ink droplets is ejected during a printing operation, which would otherwise be caused by an increase in the viscosity of ink.
There has recently arisen a demand for a large-sized ink-jet recording apparatus which uses as a recording medium, for example, a roll sheet having a width of 40 inches or more. The width and height of the recording apparatus are inevitably increased, and development of a recording apparatus which requires an operator to perform operations while remaining in a standing position is on the horizon. In the design of such a large-sized recording apparatus, consideration must be paid to enabling images to be printed on paper having the maximum width, as well as on, e.g., A3-size paper.
Recording paper having various widths is loaded on the recording apparatus with reference to the home position, where capping unit is disposed, and awaits the recording head. The carriage having the recording head mounted thereon is controlled so as to travel back and forth in the widthwise direction of the thus-loaded recording paper. Consequently, the distance over which the carriage travels can be reduced, thereby improving throughput of the recording apparatus.
In association with an increase in the capability of producing a large volume of prints and an increase in print speed, the recording apparatus must work with a large amount of ink to be discharged, even during the cleaning and flushing operations for the purpose of recovering the print function of the recording head. Because of such a necessity, the capping unit, which performs cleaning operation in conjunction with flushing operation, becomes unable to discharge a large amount of waste ink.
For this reason, dedicated flushing regions are desirably provided on opposite sides of a print area, and the recording head is subjected to flushing in these flushing regions. If the recording head is subjected to flushing while traveling at an accelerated speed at the start of print operation, throughput of the recording apparatus can be further improved.
In the above-described recording apparatus, in consideration of improvement in throughput, flushing of the recording heads is desirably limited to within the flushing region located close to the home position where the capping unit is disposed. Desirably, the recording apparatus is controlled so as to determine whether to periodically perform the flushing operation, according to the width of the paper loaded on the recording apparatus and according to whether or not printing is performed along single pass from the home position.
Meanwhile, a threshold value to be used for determining whether or not flushing operation has been performed is selected to be as great as possible, so as to prevent print throughput from being lowered. In order to ensure reliability of printing operation, flushing operation must be effected at a point in time when printing operation for one path is commenced, such that a flushing operation cycle comes during a print period corresponding to the next path, possibly even before a flushing operation cycle has come.
The present invention has been conceived on the basis of the foregoing technical grounds, and the object of the present invention is to provide a flushing control method and a flushing controller, which are applied to a recording apparatus capable of working with comparatively wide recording paper and which enable improvement in throughput.
It is another object of the invention to provide an ink-jet recording apparatus capable of performing flushing operation, so as to ensure print reliability regardless of a print mode or the width of recording paper and without involvement of a decrease in throughput.
In order to achieve the above objects, according to the present invention, there is provided an ink-jet recording apparatus comprising:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded;
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed;
means for recognizing the width of the recording medium;
means for detecting the moving direction of the carriage; and
means for determining whether the flushing operation is performed in accordance with width data recognized by the width recognizing means and direction data detected by the direction detecting means.
Preferably, the flushing determination means receives a print start instruction as an activation trigger.
Preferably, the ink-jet recording apparatus further comprises: means for physically detecting the width of the recording medium; and means for logically detecting the width of the recording medium from an input data into a printer driver. The width recognition means selects data having smaller width value from the width data detected by the physical detection means and the logical detection means.
According to the present invention, there is also provided an ink-jet recording apparatus comprising:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded;
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed;
means for detecting the moving direction of the carriage;
a timer for counting a time period elapsed from a completion of printing for each single pass;
means for determining whether the flushing operation is performed in accordance with width direction data detected by the direction detecting means when the timer counts a predetermined time period.
Preferably, in the above apparatuses, the flushing determination means further determines that the flushing operation is performed at the first or the second flushing region in accordance with the width data and the direction data.
According to the present invention, there is also provided a flushing controller incorporated in an ink-jet recording apparatus which comprises:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded; and
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed, comprising:
means for recognizing the width of the recording medium;
means for detecting the moving direction of the carriage; and
means for determining whether the flushing operation is performed in accordance with width data recognized by the width recognizing means and direction data detected by the direction detecting means.
According to the present invention, there is also provided a flushing controller incorporated in an ink-jet recording apparatus which comprises:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded; and
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed, comprising:
means for detecting the moving direction of the carriage;
a timer for counting a time period elapsed from a completion of printing for each single pass;
means for determining whether the flushing operation is performed in accordance with width direction data detected by the direction detecting means when the timer counts a predetermined time period.
Preferably, in the above apparatuses, the flushing determination means has different threshold values for the determination in accordance with the moving direction of the carriage, and determines that the flushing operation is performed when time period elapsed from a completion of previous flushing operation exceeds the threshold value.
In this case, the threshold value considered when the carriage moves toward a home position of the recording head is larger than the threshold value considered when the carriage moves from the home position. Preferably, one of the threshold values includes a delay factor for delaying the carriage starting every single pass of print scanning for a time period which is enough to dry the ink of previous pass.
In this case, preferably, the difference between the threshold values includes the delay factor, a time period required for single pass of printing on the recording medium, and a predetermined margin.
Preferably, the above controllers further comprise: means for physically detecting the width of the recording medium; and means for logically detecting the width of the recording medium from an input data into a printer driver. The width recognition means selects data having smaller width value from the width data detected by the physical detection means and the logical detection means.
Preferably, in the above controllers, the flushing determination means further determines that the flushing operation is performed at the first or the second flushing region in accordance with the width data and the direction data.
According to the present invention, there is also provided a flushing control method used for an ink-jet recording apparatus which comprises:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded; and
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed, comprising the steps of:
recognizing the width of the recording medium;
detecting the moving direction of the carriage; and
determining whether the flushing operation is performed in accordance with width data recognized by the width recognizing step and direction data detected by the direction detecting step.
Preferably, execution of the steps is activated by a print start instruction.
Preferably, the method further comprises the steps of:
detecting the width of the recording medium physically;
detecting the width of the recording medium logically from an input data into a printer driver; and
selecting data having smaller width value from the width data detected by the physical detection step and the logical detection step as the width data.
According to the present invention, there is also provided a flushing control method used for an ink-jet recording apparatus which comprises:
an ink-jet recoding head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which an image is to be recorded; and
a first and a second flushing regions situated opposite ends of the printing region in which a flushing operation of the recording head is performed, comprising the steps of:
counting a time period elapsed from a completion of printing for each single pass;
detecting the moving direction of the carriage when a predetermined time period is counted; and
determining whether the flushing operation is performed in accordance with width direction data detected by the direction detecting step.
Preferably, in the above methods, the flushing determination step further determines that the flushing operation is performed at the first or the second flushing region in accordance with the width data and the direction data.
According to the above configuration, a determination is made as to whether or not flushing operation is to be performed, according to at least the direction in which the carriage is to travel in the next printing operation. Consequently, the determination can be made with estimation of the time required to print the next single pass. Flushing intervals required by the recording heads can be ensured, and reliable printing can be ensured.
In addition, the threshold value to be compared with the time elapsed from completion of the previous flushing operation is set to different values according to the traveling direction of the carriage. For example, the threshold value can be controlled such that the probability of the recording heads being subjected to flushing within the flushing box in the vicinity of the home position is increased, thus ensuring reliable printing and improving printer throughput while the range of travel of the carriage is reduced.
According to the present invention, there is also provided an ink jet recording apparatus comprising:
an ink jet recording head mounted on a carriage reciprocatively moving in a width direction of a loaded recording medium having a printing region on which image is recorded;
at least one flushing region situated at least one of opposite side ends of the printing region, in which a flushing operation of the recording head is performed;
means for setting a reference value which is determined in accordance with a first time period required for the carriage to travel a width dimension of the loaded recording medium;
means for setting a threshold value, which is used for determining whether the flushing operation is performed, in accordance with the reference value;
a timer which is reset when the flushing operation is performed; and
means for determining whether the flushing operation is performed by comparing the threshold value and a time period counted by the timer.
Preferably, the reference value is determined in accordance with the width dimension of the loaded recording medium.
Further, it is preferable that the reference value is determined in accordance with a moving speed of the carriage.
Still further, it is preferable that the reference value is determined in accordance with a second time period which is obtained by subtracting the first time period from a maximum time interval between succeeding flushing operations.
Preferably, the recording medium is loaded such that a reference position thereof is placed in a side of which a home position of the carriage is situated. Here, the threshold value determination means has different threshold values in accordance with the moving direction of the carriage. A first threshold value used for a printing when the carriage moves from the home position is smaller than a second threshold value used for a printing when the carriage moves toward the home position.
Here, it is preferable that the first threshold value is obtained by subtracting a predetermined value from the reference value.
Preferably, the at least one flushing region includes a first flushing region which is situated in one side end of the printing region where a home position of the carriage is placed, and a second flushing region which is situated in the other side end of the printing region. Here, the recording apparatus further comprises means for selecting the first flushing region or the second flushing region where the flushing operation is performed when the flushing operation determination means determines the flushing operation is required.
In the above configurations, the reference value is decreased as the carriage travel time of the carriage becomes longer, in accordance with the width dimension of recording paper loaded on the recording apparatus and the moving speed of the carriage, thereby increasing the frequency of flushing operation. Thus, the reliability of printing operation is ensured. When the travel time period of the carriage is short, the reference value is increased, thus decreasing the frequency of flushing operation. Accordingly, throughput of the recording apparatus can be improved.